多维列表内一部分字符串型转换为整型

Question

shell.txt
a1 b1 0.2 0
a1 c1 0.8 0
b1 c1 0.7 0
a2 b2 1 0
a2 d2 0.4 0
d2 b2 0.6 0
a1 a2 1 1
a2 a1 0.1 1
b1 b2 0.5 1
b2 b1 0 1

with open('shell.txt') as f:
    lines = f.readlines()
mylist = [line.strip().split() for line in lines]

由于txt数据加载后均为字符串型，现需要讲后两列转换为整型，求大佬给些clean的方法，谢谢

Answer 1

result = []
for i in f:
    s = i.split()
    result.append(s[:-2]+map(lambda x: int(float(x)), ss[-2:]))
print result